面向海上安全信息广播系统的波形关键技术研究

Waveform Design for Maritime Safety Information Broadcasting Systems

新一代海上安全信息广播系统(Navigational Data,NAVDAT)采用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术实现高速率数字广播,然而,带外辐射以及由海上通信节点的运动和电离层运动引发的频率偏移等问题限制了其性能的进一步提升。针对上述问题,探讨了滤波器组多载波(Filter Bank Multicarrier,FBMC)、广义频分复用(Generalized Frequency Division Multiplexing,GFDM)、通用滤波多载波(Universal Filtered Multicarrier,UFMC)三种未来移动通信参考波形在NAVDAT系统中的应用前景,给出了三种波形调制解调原理,阐明了其优缺点,并对其在海上无线信道下的系统性能进行了仿真分析。分析结果表明,相比于OFDM,三种参考波形具有更低的带外辐射和更高的频谱效率,可进一步提升NAVDAT系统的数据传输速率。此外,UFMC和FBMC可以有效对抗海上无线信道的频率偏移问题。然而,与现有OFDM技术相比,三种波形面临兼容性差、抗干扰能力差、复杂度高等挑战。最后,基于分析结果给出了未来的研究方向。

As a new generation of maritime safety information broadcasting system,the Navigational Data(NAVDAT)system em⁃ploys Orthogonal Frequency Division Multiplexing(OFDM)to provide high⁃rate digital broadcasting services.However,the disadvantages of OFDM,such as out⁃of⁃band emission,frequency offset caused by both the mobility of maritime users and the ionosphere motion,hinder the further development of NAVDAT.To solve the above⁃mentioned issues,three waveform candidates,known as Filter Bank Multicarrier(FBMC),Generalized Frequency Division Multiplexing(GFDM)and Universal Filtered Multicarrier(UFMC),as well as the prospect of applying them to the NVANAT system,are discussed.First,the modulation and demodulation processes of these candidates are described,and their pros and cons are analyzed.Next,simulations are carried out by adopting maritime wireless channels.Simulation results show that compared with OFDM,the waveform candidates can achieve lower out⁃of⁃band emission and higher spectral efficiency,which can further increase data rate of the NAVDAT system.In addition,UFMC and FBMC can effectively combat the problem of frequency offset in maritime wireless channels.Finally,challenges faced by the three waveform candidates in terms of system compatibility,interference mitigation,system complexity,are discussed as future research directions.